If entries on expert gardening sites are any indication, dying palm trees are a fairly common problem. Diagnosing a problem at a distance can be challenging, but it's likely that one in a handful of common causes is killing the tree and some deductive work can narrow the options. Some palm trees can benefit from triage efforts and regain their vitality, while others will have to be taken down at some point before they become a hazard.
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There could be a disease or fungus in the tree and or the surrounding soil that is deadly to palm trees as has occurred in large palm tree populations in Los Angeles. If other palms in your area seem to be failing or dying off, this may indicate that a spreading disease is affecting the palms. Sadly, there is no cure but to remove the palm tree and plant a non-palm variety that is not affected by the fungus.
There are many varieties of palms that are monocarpic, meaning that they fruit once and then die. These palms can take many decades to reach a mature fruiting point, so it doesn't mean that it begins to die once it completes its bloom cycle. The water and soil conditions could be off and the roots and plant have either dessicated from lack of water or rotted from too much of it. If your palm has produced unusual flowers or fruit in the last year or two, this could be your problem.
Water, Soil or Sun Exposure Issues
The most common affliction of all underperforming plants are imbalances in their environmental conditions. Scorching sun with drought conditions can weaken and kill a palm as can overwatering in soil that is not well drained. Carefully inspect the soil conditions around the palm, digging down into the soil several feet to see what is going on beneath the surface. If you find extremely dry or extremely wet conditions, you may be able to turn back the clock by correcting the imbalance. If a portion of the foliage has been burnt or scorched by sun, cut it away with clean pruning shears or loppers. This will give you a better view to see new growth which is a sign of recovery.